Scott Johnson says that there good reason that many Republicans have not backed Romney and instead continue to explore alternatives:
The inclination of Republican primary voters and caucus goers to support Gingrich or Santorum is not the sign of a character flaw or mental defect on their part. It is a sign that Romney is a problematic candidate for the party whose standard bearer he seeks to be. Decrying the failure of Republican voters for failing to fall in line behind him seems to me something less than a winning argument.
Note to Romney supporters: at this point in the campaign, launching attacks against those who have so far refused to jump on the bandwagon for your candidate is not a good idea. It will hurt Romney and the lessen the liklihood that Republicans will be able to unify after the primaries to defeat President Obama. Instead of blaming conservatives for not taking to Romney, you should be asking why Romney has thus far failed to seal the deal. There are still things Romney could do to at least cause conservatives to come around (however reluctantly) to accept him as the nominee. There have been no shortage of such suggestions made by Romney supporters among the right wing punditry, yet the campaign seems curiously reluctant to embrace any of them. Until that changes, don't blame for not settling for an inferior product.